科学美国人60秒 SSS DNA新途径（在线收听）

Ancient Human DNA Found in Cave Dirt DNA新途径

Fossilized skulls and skeletons found in European caves gave us our first glimpse of our ancient cousins, the Neandertals. And a finger bone, found in a Siberian cave, first indicated the existence of another relative—the Denisovans. But fossils are hard to come by. So here's another option: analyze cave floors to see if it contains any DNA.

在欧洲洞穴发现的头骨和骨骼化石让我们第一次了解到我们古代的表亲尼安德特人.在西伯利亚一个洞穴发现的手指骨,也首次证实了我们另一个亲属丹尼索亚人的存在.但是,化石很难得到.另一种办法就是分析洞穴层中含有的DNA.

"We find ancient hominins, we find Neandertal mitochondrial DNA, and Denisovan mitochondrial DNA."

“我们发现古人类,发现穴居人的线粒体DNA,和丹尼索瓦人的线粒体DNA。”

Viviane Slon, a geneticist at the Max Planck Institute in Germany.

Viviane Slon,德国马克斯普朗克研究所的遗传学家。

She and her team found that molecular evidence by testing teaspoonfuls of sediment from seven different caves. And they screened specifically for mitochondrial DNA—because there's a lot more copies of it in cells compared to nucleus DNA, which has just one set per cell.

她和团队们,通过检测7个不同洞穴中的少量沉积物发现了分子证据.他们专门检测了线粒体DNA——因为与核DNA(每个细胞中仅有一个核DNA)相比，细胞中有多份线粒体DNA。

The researchers uncovered genetic evidence of Denisovans where you might expect—at Denisova Cave in Siberia. Which showed that their strategy was sound. They found Neandertal DNA there too, and at three of the other seven caves—including a cave where no Neandertal fossils have ever been found, only artifacts and animal bones.

研究人员在西伯利亚的丹妮索瓦洞中发现了期望中的丹妮索瓦人的基因证据。基因显示，他们的策略是正确的。因为在那里也发现了尼安德特人的DNA，在7个洞穴中其他三个洞穴里——其中有一个洞穴中没有发现任何尼安德特人的DNA，只发现了工艺品和动物骨骼。

And they found the DNA of some surprise guests, too: "The woolly mammoth, or the woolly rhino. We have cave hyenas and cave bears." The study is in the journal Science.

研究人员还发现了一些意外客人的DNA：长毛象，长毛犀。还有洞穴鬣狗和洞穴熊。该研究结果发表在《科学》杂志上。

This preliminary success, Slon says, means the method could be a good complement to traditional surveys. "We're not trying to replace working on ancient DNA from fossils, but rather open all the archaeological sites where there are no hominid fossils for genetic analyses." Leading, hopefully, to a broader census of our ancient relatives. No bones about it.

Slon 表示，初步的成功意味着这种方法是对传统检测方法很好的补充。“我们并不是要取代对化石中古代DNA的研究，”而是要打开基因分析显示没有原始人类化石的考古遗址。”希望，这将引领对古代亲戚的更广泛的普查。这一点毫无疑问。